Multistage process for preparing organopolysiloxanes comprising aminoalkyl groups

Abstract

Organopolysiloxanes having aminoalkyl groups are prepared by (i) reacting (A) linear, cyclic or branched organopolysiloxanes with (B) aminoalkyl silanes having an SiC-bonded hydrocarbon radical comprising basic nitrogen and 2 or 3 hydrolyzable groups, or partial or full hydrolyzates thereof, in the presence of (C) basic catalysts and optionally (D) chain-terminating reagents, at a temperature of at least 60° C., then, after the reaction (i), (ii) deactivating the catalysts (C) and (iii) cooling the product to a temperature below 60° C. before, during or after the deactivation (ii) of the catalysts, with the proviso that the process is performed in at least two successive stirred tanks, the reaction (i) and the cooling (iii) proceeding separately in different stirred tanks.

1. A batch process for preparing organopolysiloxanes having aminoalkyl groups comprising
 (i) reacting at a temperature of at least 60° C.,
 (A) at least one organopolysiloxane selected from the group consisting of linear organopolysiloxanes with 
 (B) aminoalkylsilanes which comprise at least one SiC-bonded hydrocarbon radical comprising basic nitrogen, and 2 or 3 hydrolyzable groups,
 or partial or full hydrolyzates thereof, 
 
 in the presence of 
 (C) basic catalysts, and 
 (D) optionally in the presence of chain-terminating reagents, 
 then, after the reaction (i), 
 
 (ii) deactivating the basic catalyst(s) (C) and 
 (iii) cooling the reaction products to a temperature below 60° C., the cooling (iii) being effected before, during or after the deactivation (ii) of the catalysts, 
 with the proviso that the process is performed in at least two successive stirred tanks, the reaction (i) and the cooling (iii) proceeding separately in different stirred tanks wherein the reaction (i) is carried out in a first stirred tank and the deactivation (ii) and cooling (iii) in a downstream second stirred tank, with the further proviso that, while the deactivation (ii) and the cooling (iii) proceed in the second stirred tank, the reaction (i) of reactants newly supplied to the first stirred tank is simultaneously proceeding in the first stirred tank. 
 
     
     
       2. The process of  claim 1 , wherein the deactivation (ii) proceeds in the same stirred tank as the reaction (i), in the same stirred tank as the cooling (iii), or in a dedicated stirred tank separately from the reaction (i) and the cooling (iii). 
     
     
       3. The process of  claim 1 , wherein the cooling (iii) proceeds after the deactivation (ii). 
     
     
       4. The process of  claim 1 , wherein the reaction (i) proceeds in a first stirred tank and the cooling (iii) in a downstream second stirred tank, the deactivation (ii) proceeding either in the first or in the second stirred tank, with the proviso that, while the cooling (iii) proceeds in the second stirred tank, the reaction (i) of the reactants newly supplied to the first stirred tank is simultaneously proceeding in the first stirred tank. 
     
     
       5. The process of  claim 1 , wherein the reaction (i) is performed at a temperature of from 60 to 180° C. 
     
     
       6. The process of  claim 1 , wherein the cooling (iii) is effected to a temperature of from 20 to 55° C. 
     
     
       7. The process of  claim 1 , wherein the deactivation (ii) is effected by neutralization or thermal decomposition of the basic catalyst(s) (C).